新型单级Buck-Boost光伏逆变器研究

Study on novel single stage photovoltaic buck-boost inverter

提出了一种新型单级Buck-Boost光伏逆变器的拓扑结构。该拓扑只需要五个功率开关和两个电力二极管,结构简单紧凑,无需直流分裂电容,开关频率低,通过占空比的调节,能在一个功率级内产生幅值高于或低于输入直流电压的交流电压,适用于AC模块。详细分析了所提逆变器的工作原理,并利用状态空间平均法建立了系统数学模型。利用串联谐振环节能实现所有开关的零电流开通和辅助开关的零电流关断,减小了开关损耗,提高了系统效率。采用SPWM控制方法,在Matlab/Simulink环境下建立了控制系统的仿真模型。仿真结果验证了该变换器的优点和SPWM控制方法的有效性。

A novel single-stage Buck-Boost PV inverter topology was proposed,which included only five switches and two power diodes,with a compact structure and low switch frequency.It did not have a DC capacitor,could generate an AC output voltage larger or lower than the input one in a single stage,and could be used in AC module.The operation principle was analyzed in detail and the mathematics model was founded by the state-space average method.The new inverter circuit topology provided all the switches for turn-on and the auxiliary switches for turn-off at zero current switching（ZCS）by a resonant tank,so that the switching loss was reduced and the system efficiency was improved.The simulation of the control system was constructed in Matlab/Simulink by SPWM control method.The simulation results show that the validity and effectiveness of the proposed inverter is verified.